Recently, various wireless communication technologies are developing in accordance with development of an information communication technology. Among the various wireless communication technologies, wireless LAN (WLAN) corresponds to a technology enabling a user to access the Internet in wireless in a home, an enterprise or an area to which a specific service is provided using such a portable terminal as a PDA (personal digital assistant), a laptop computer, a PMP (portable multimedia player) and the like based on a radio frequency technology.
In order to overcome a limitation on communication speed, which is blamed for a weak point of WLAN, a recent technology standard has introduced a system of which network speed and reliability are increased and managing distance of a wireless network is extended. For instance, IEEE 802.11n supports HT (high throughput) that maximum data processing speed is greater than 540 Mbps and application of MIMO (multiple inputs and multiple outputs) technology using multiple antennas at both an transmitting end and a receiving end is introduced to minimize a transmission error and optimize data speed.